Mobile devices, such as radios and cellular telephones, typically rely on power from one or more internal batteries. A major performance criterion for such devices is the battery life, which is typically defined as the time period for which the battery will power the device on a single charge. A large portion of the battery power is consumed in a power amplifier (PA) section of the mobile electronic device's transmitter. The power amplifier section amplifies the power of a signal to be transmitted from a comparatively low internal power level to a substantially higher power level required for wireless communication with remote base stations or other devices.
Power efficiency is even more important with multimedia services that consume significantly more power than traditional voice communication services. Thus, improving the power amplifier efficiency or, more generally, transmitter efficiency, is an important factor in battery life performance.